Portable speaker



FIG. 1 is a front perspective view of a portable speaker showing my new design;

FIG. 2 is front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a side elevational view thereof;

FIG. 5 is a bottom plan view thereof; and,

FIG. 6 is a top plan view thereof.

The broken line showing on the drawing disclosure is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portable speaker, as shown and described. 